Heat setting of footwear

ABSTRACT

Heat-setting footwear by advancing same through closed chamber in which hot, moisture-saturated air is circulated. Moisture saturation maintained by hot air passing over shallow evaporation tank continuously supplied with water via a ball valve. Airheating coils in chamber controlled by temperature-responsive device adjacent footwear being treated so as to maintain temperature constant. Also discloses plurality of spaced unitconstruction heat-setting chambers in conjunction with chain conveyor.

United States Patent [72] In n Alfred Freeman 2,182,620 12/1939 Cano 34/46X 94 Orlingburg Road. m, 2,201,389 5/1940 Degive 34/46 Northamptonshire, England 2,255,714 9/1941 Rodelli 160/332 [21] Appl. No. 762,234 2,295,475 9/1942 Hurxthal 34/225X [22] Filed Sept. 16, 1968 2,363,715 11/1944 Wells 34/225X [45] Patented May 25,1971 2,552,387 5/1951 Whinery.... 34/4 [32] Priority Sept. 21, 1967 3,220,033 11/1965 Bromfield et al. 12/lA [33] Great Britain 3,249,150 5/1966 Knight l60/332X [3 l 909/67 Primary ExaminerCarroll B. Dority, Jr

Attorney-Larson, Taylor and Hinds [54] HEAT SETTING 0F FOOTWEAR 6 Claims, 5 Drawing Figs.

[52] US. Cl 34/48,

34/212, 34/216, 34/219 ABSTRACT: Heat-setting footwear by advancing same [51] Int. Cl F26b 19/00 through closed chamber in which hot, moisture-saturated air [50] Field of Search 34/26, 28, is circulated. Moisture saturation maintained by hot air 46, 50, 212, 215, 216, 219, 224, 225, 48; 12/1 (A), passing over shallow evaporation tank continuously supplied 41.5, 59.7 with water via a ball valve. Air-heating coils in chamber controlled by temperature-responsive device adjacent footwear [5 6] References C'ted being treated so as to maintain temperature constant. Also dis- N ED TA E P TENT closes plurality of spaced unit-construction heat-setting cham- 1,853,419 4/1932 Harris 34/26 hers in conjunction with chain conveyorr e N u. 1 \.2-.;: ..-"T IZ" :IEiiil: lilifilEfiiQ'jIl': 122-1:

i 20 JF r v t y PATENTEU W25 l9?! SHEET 1 [1F 3 i l I l I I I Fu iw HEAT SETTING OF FOOTWEAR This invention is concerned with the process of heat setting found that the degree of humidity of the atmosphere through.

which this work is passed has an all-important bearing on the efficient processing of the leather at this setting stage and that previous methods of treatment have neglected this aspect.

To remedy this, the present invention provides a method of heat setting footwear (which term includes complete articles of footwear or components thereof at any convenient stage of manufacture, preparation, or after-treatment) in which the footwear is advancedlat a controlled rate through a chamber in which hot air is circulated and maintained at a preset temperature and pressure and is kept moisture-saturated for this temperature and pressure.

The invention further provides an apparatus for heat-setting footwear, which includes relatively simple and convenient means to maintain the moisture-saturation of the air. This comprises a closed chamber having means for producing a circulation of air therein, means for heating the air and an evaporation device which is heated by the circulating air and is adapted to be continuously supplied withwater for evaporation by the device.

With this apparatus in use, the hot air, in circulating, heats up the evaporation device and water which evaporates. When the temperature of the latter reaches 1 100 C. it starts to boil.

The moisture content of the air continues to increase andfootwear into the chamber, is started so that the work is ad-- vanced through an atmosphere which is maintained constantly maximum-saturated.

The duration of the treatment can be controlled by varying the speed of the'conveyor and this in turn depends on the temperature in the chamber and the nature of the work.

According to a preferred embodiment of the'invention, the evaporator device may simply comprise a shallow trough or tank which is supplied with water through a ball valve arranged to maintain a shallow covering of water over the' bottom of the tank or trough. A pump may be provided to produce a circulation or water in the tank or trough to assist the evaporation.

Preferably, the tank or trough is adapted to be heated by means additional to the hot air. For example, it may be positioned in the chamber, adjacent the air heaters. Where one side of the tank or trough is so positioned, a temperature differential is set up between the opposite sides thereof. This sets up convection currents which cause the water to circulate and thereby obviate the need for a circulatory water pump.

In an alternative embodiment, the evaporator device in question may comprise a corrugated sheet of .copper or other conductive material and hot water is trickled down' the grooves in this sheet, which for the purpose may be arranged vertically, inclined to the vertical, or even in substantially horizontal disposition. A sprinkler tube may be arranged above this sheet, with its discharge orifices positioned to direct water from the tube down the valleys in the plate, to be collected in a header at the bottom of the. plate and returned, by a circulating pump to the sprinkler tube.

In order that the invention may be more clearly understood and readily carried into practical effect, specific embodiments thereof will now be described with reference to the accompanying drawings, wherein FIG. I is a front view, with the front wall omitted, of an apparatus for heat-setting footwear, constructed in accordance with the invention,

FIG. 2 is a vertical sectional view on line II-ll of FIG. 1,

FIG. 3 is a front view showing a unit construction footwear treatment station incorporating a modified. form of heatsetting chamber of the kind illustrated in FIGS. 1 and 2 in conjunction with a chain conveyor,

FIG. 4 is a vertical sectional view on line IV-IV ofv FIG. 3, and

FIG. 5 is a schematic circuit diagram of the control circuit for theheating coils of FIG. 1.

The apparatus shown'in FIGS. 1 and 2 is positioned at an appropriate point along a chain conveyor 1 with the latter passing through it and carryingfootwear F to be treated by the apparatus. The .latter comprises achamber 2 constituted by a.

metal channel-section-and angle-section framework 3 having front and rear sheet metal panels 4 secured thereto. The lower part of the chamber is separated from the upper part by a horizontal partition 5 and constitutes a closed compartment 6. As'can be seen from FIG. 2, compartment6 isdeeper from back to front than chamber 2, extending beyond the rear wall thereof.

Chain conveyor 1 extends through the upper part of the chamber 2 from end to end thereof and,.as mentioned above, carries footwear F for'heat setting. The end walls of chamber 2 above the'compartment 6 are closed by flap doors 7 which allow the conveyor- 1 to pass therethrough but which discourage loss of hot air. These doors are in the embodiment illustrated, constituted by metal strips 8 arranged side by side to form a continuous curtain and depending from a rod 9 between the front and'rear walls of the chamber. Two such flap doors 7 are provided at each end of the chamber and-are arranged one above the other.

Two vertical partitions l0-extend rearwardly from thefront wallof compartment 6 eachat a position approximately a third of the way along the. wall, and terminate at positions immediately belowthe rear wall of chamber 1'. Each partition 10 is of a depth'equal to that offthe compartment. Positioned inwardlyv of partitions 10 and defining with-the latter, a-pair of narrow elongate chambers 11, are a further pair of partitions 12. These partitions extend downwardly from the horizontal partition 5 over approximately two-thirds of the depth of com partment 6' and rearwardly fromthe front wall'of the-latter, terminating at their rear edges, level with the partitions 10.

A rectangular aperture 13 is provided in the horizontal partition 5 above each chamber 11 and is of the same size as the cross section of the latter. Positioned a short distance above each aperture and secured between the front and rear walls of chamber 1' is a cover plate 14, gauze grill15'being provided between the'longitudinal edges of each cover plate and the partition 5.

A rectangular aperture 16, similar toapertures 13 and parallel thereto, is also'provided in-partition 5 in each part thereof between the-relevant end wall of the chamber 2 and the adjacent partition 10. Securedwithin each of the apertures 16 are a plurality of closely-spaced jet tubes 17 which direct air-through the partition 5 as will be explained.

Located in each of the above-mentionedv chambers 11 are a plurality of electrical heating coils 18 for heating air in thesehorizontal partition 5. Tubes 17 ensure that the air is expelled.

vertically and is kept'away from the ends of the chamber;2 to minimize the possibility of heat loss through the flap doors 7. On leaving the tubes 17, the air, which-is hot, rises towards the top of chamber 2. It then'cools and is, drawn down into the chambers to be reheated. Continuous circulation of air is therefore produced, the paths of theair-being indicated by arrows in FIGS. 1 and 2.

A temperature-responsive device of conventional form, shown diagrammatically in FIG. I at 20,- is provided in the chamber 2 in the path of the circulatingair. This device is connected in the electrical supply to the heating; coils I8 and.

serves to regulate their heat output and so maintain the air temperature constant at a preset value depending on the type and condition 'of the footwear being treated, say 1 10 C. Control of the heat output may be effected either by reducing the current supply to all of the coils or by switching off certain of them. Thus, referring to FIG. 5, the output of a pair of heater coils 18 is controlled by a switch S1 responsive to the temperature-responsive device 20 of FIG. 1. Switch S1 is connected in shunt with one coil of the two coils 18 and selectively shorts out that coil responsive to movement of temperature-responsive device 20. A further switch 26, connected in series with heater coils 18, is discussed hereinbelow.

A shallow metal trough or tank 21 is welded at one side to the exterior surface of the partition 10 shown at the right-hand side of FIG. 1. .Water is supplied to the tank 21 from a water main (not shown) through a ball valve 22 which controls the water flow so as to maintain a depth of about l inch of water on the bottom of the tank. When the apparatus is in use, the water is heated by the circulation of hot air in chamber 2 and, in addition, the water at the end of the tank adjacent the partition 10, is heated by the heating coils 18 in chamber 11. The water at this end of the tank therefore eventually boils. The temperature differential existing between the opposite ends of the tank causes convection currents to be set up so that the water circulates. After a time, the water boils throughout the tank. The temperature of the water is maintained by the increasingly hot air.

When the air temperature reaches the value preset by the device 20, it remains at this level and the air continues to pick up moisture until it is fully saturated for that temperature and pressure.

At this stage, or even a little before, the advance of the conveyor 1 is commenced and continued, so that the work is advanced thereby through an atmosphere which is maintained constantly maximum-saturated.

This gives an accurate control of the work-treatment conditions. The duration of this treatment can be controlled by selection of the speed of advance of the conveyor. It may be found advantageous to provide for periods of dwell in the movement of chain to cater for a prescribed treatment period.

Instead of merely controlling the output of the heating coils 18 by the regulator device 20, the latter may be connected to the driving means of the conveyor I and may serve to regulate its speed according to the prevailing temperature in the chamber 2, i.e. the higher the temperature, the faster the conveyor would be driven, so that each footwear article is treated for a progressively shorter period as the temperature rises.

As a safety device to prevent damage to the heating coils should the fan 19 break down or the airflow be obstructed, a flap 23 secured to a spindle 24 turnably mounted in, and projecting through, the rear wall of the chamber 2, is positioned in the airstream adjacent the partition 10 shown at the lefthand side of FIG. 1. At the exterior of the rear wall of the chamber, an arm 25 is fixed to spindle 24 and a switch 26 mentioned above is positioned forcontact by this arm. The arrangement is such that the air flow past flap 23 normally maintains it in position in which arm 25 is held away from switch 26. However, should the airflow stop flap 23 returns to a vertical rest position and arm 25 actuates the switch 26. As shown in FIG. 5, switch 26 is connected in series in the electrical supply to the heater coils 18 so as to switch them ofi' in the event that the airflow stops.

The apparatus so far described comprises a single heated chamber primarily for application to an existing conveyor system for heat setting footwear. On the other hand, FIGS. 3 and 4 show heat setting apparatus including two heated chambers incorporating part of a chain conveyor system. This apparatus is of unit construction for easy assembly and also to enable its size to be easily varied, four units being illustrated.

Each unit comprises an inverted channel-section member 27 arranged in a horizontal disposition and having a track-section 28 for the wheels of a conveyor 1 welded to the interior surface of its outer wall. A circular-section rod 29 having a threaded spigot 29 a projecting from each end is arranged vertically adjacent each end of each member 27, the spigot at the relevant end of each rod passing through a complementary hole in the base of the channel member adjacent the inner wall 21b and being retained by a nut 30. A sheet metal plate 31 is welded between these upright rods and forms a back member.

The lower spigots 29a pass through holes in a horizontal base plate 32 disposed parallel to and directly below the base of member 27, an upstanding lip 32a being provided along its outer longitudinal edges. A sheet metal cover or facing 33 is arranged to be bolted to the outer wall 27a of channel member 27 and to lip 32a to cover in the front of each unit.

In the drawings, four such units are shown side by side, being connected together by bolts 34 through their adjacent rods 29. As can be seen from FIG. 4, in the particular assembly illustrated the units each have a duplicate partner, each pair being disposed back to back and secured by bolts through the adjacent sides of their channel members 27. Of course, it is not essential that the units be duplicated. A single row of units may be employed if appropriate.

The base plate 32 of the extreme right-hand unit and of the next but one unit thereto each constitute the top of a compartment identical with the compartment 6 shown in FIGS. 1 and 2, i.e. each alternate unit is in the form of a heat chamber capable of providing a circulation of moisture laden air. The conveyor track incorporated in the units bolts directly onto external continuation track sections 35 of the conveyor system, these track sections 35 being arranged to slope downwards from the point of connection with the units as can be seen. Since hot air rises, this inclination of the external sections, ensures that when the apparatus is in operation, the hot air produced by the heat chamber units is trapped, being retained by the channel members 27 and the facing covers 33 and being prevented from escaping at the ends of the assembly by the downwardly-sloping external sections. It will be appreciated that there are no partitions between adjacent units, the hot air flowing along therebetween.

Depending on the conditions required which in turn depends on the type of footwear being treated, the water supply to one of the heat chamber units may be terminated if desired, so that one wet" and one dry heat chamber is employed.

If desired, one or more of the walls of the chamber may incorporate a heat insulating material so as to minimize heat losses therethrough. In fact, the walls may be constituted by reinforced plastics mouldings incorporating heat insulating material. In the embodiment illustrated-in FIGS. 1 and 2, the front and rear walls 4 and in the other embodiment, the covers or facings 33 may each be made of such a moulding.

I claim:

1. Apparatus for use in the heat setting of complete articles of footwear or components thereof, comprising a heat-setting chamber through which said articles or components are advanced; means for producing a circulation of air in said chamber; means for heating the air; an evaporation device which is heated by the circulating air; means for supplying water to the device for evaporation thereby; a flap positioned in the path of the circulating air; a spindle turnably mounted in a wall of the heat-setting chamber and carrying said flap; and a switch which controls said means for heating the air and is arranged to be operated in response to turning of said spindle so as to switch off said heating means in the event that the air circulation is obstructed as detected by return of the flap to a rest position.

2. Apparatus according to claim 1, wherein the ends of the heat-setting chamber are provided with at least one flap door which comprises a curtain of metal strips suspended side by side from their upper ends so as to discourage heat loss through the ends of the chamber whilst allowing the passage therethrough of a conveyor carrying articles of footwear or footwear components by deflection of at least one of said strips.

3. Apparatus according to claim 1, wherein the evaporation device comprises a shallow tank, and wherein the means for supplying water to the device comprises a ball valve in the tank arranged to maintain a shallow covering of water over the bottom of the latter.

4. Apparatus according to claim 3, wherein the tank is positioned in the chamber with one side thereof adjacent said means for heating the air, whereby a temperature differential is produced across the tank which sets up convection currents in the water and promotes circulation of the latter.

5. Apparatus according to claim 12, wherein said heating means are constituted by electrical heating coils positioned in at least one heating chamber within the heat setting chamber and wherein the means for producing a circulation of air com- 

1. Apparatus for use in the heat setting of complete articles of footwear or components thereof, comprising a heat-setting chamber through which said articles or components are advanced; means for producing a circulation of air in said chamber; means for heating the air; an evaporation device which is heated by the circulating air; means for supplying water to the device for evaporation thereby; a flap positioned in the path of the circulating air; a spindle turnably mounted in a wall of the heat-setting chamber and carrying said flap; and a switch which controls said means for heating the air and is arranged to be operated in response to turning of said spindle so as to switch off said heating means in the event that the air circulation is obstructed as detected by return of the flap to a rest position.
 2. Apparatus according to claim 1, wherein the ends of the heat-setting chamber are provided with at least one flap door which comprises a curtain of metal strips suspended side by side from their upper ends so as to discourage heat loss through the ends of the chamber whilst allowing the passage therethrough of a conveyor carrying articles of footwear or footwear components by deflection of at least one of said strips.
 3. Apparatus according to claim 1, wherein the evaporation device comprises a shallow tank, and wherein the means for supplying water to the device comprises a ball valve in the tank arranged to maintain a shallow covering of water over the bottom of the latter.
 4. Apparatus according to claim 3, wherein the tank is positioned in the chamber with one side thereof adjacent said means for heating the air, whereby a temperature differential is produced across the tank which sets up convection currents in the water and promotes circulation of the latter.
 5. Apparatus according to claim 12, wherein said heating means are constituted by electrical heating coils positioned in at least one heating chamber within the heat setting chamber and wherein the means for producing a circulation of air comprises a fan positioned to draw air downwardly through the at least one heating chamber, over the heating coils, the hot air passing out of said heating chambers being directed vertically and then being drawn again through said heating chambers and recirculating.
 6. Apparatus according to claim 5, wherein a temperature-responsive device is provided in the heat-setting chamber and is connected in the electrical supply to said heating coils so as to vary the heat output according to the temperature prevalent in the main chamber. 